1. Tissue Engineering Laboratories, VA Boston Healthcare System, MS 151, Boston, Massachusetts 02130, United States
2. Department of Orthopaedic Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States
3. Department of Orthopaedic Surgery, Yong Loo Lin School of Medicine, National University of Singapore, 27 Medical Drive, Singapore 117510
4. Faculty of Dentistry, National University of Singapore, 11 Lower Kent Ridge Road, Singapore 119083